1. Related Technical Fields
Related technical fields include systems, methods, and programs that provide guidance based on traffic congestion.
2. Description of Related Art
In recent years, navigation apparatuses that carry out vehicle travel guidance and enable a driver to arrive at a desired destination easily are commonly mounted in vehicles. A navigation apparatus denotes an apparatus that detects the current position of a vehicle by using a GPS receiver or the like, and enables the displaying of map data that corresponds to the current position on a liquid crystal display. The map data is obtained from a recording medium such as a DVD-ROM, an HDD, or the like, or from a network. In addition, the map data that includes the current position of the vehicle is read from the recording medium, and a map image for the vicinity of the current position of the vehicle is rendered based on the map data and is displayed on a display apparatus. The map image may be displayed with a vehicle position mark superimposed thereon, and the location at which the vehicle is currently traveling can be recognized at a glance by scrolling the map image in association with the movement of the vehicle or moving the vehicle position mark over the map image that is held stationary on the screen.
In this context, various navigation apparatuses have been proposed in which the guidance route is based on received road traffic information and the congested congestion road links that are included along this guidance route are distinctly displayed.
For example, road traffic information is received externally and the congestion road links are distinctly displayed on the map. It is determined whether congestion road links are present along the guidance route based on the received road traffic information. In the case in which congestion road links are present, a display scale is determined that enables displaying the vehicle position and the endpoint of the congestion along the guidance route on one screen. At this scale, maps, the guidance routes, and the traffic congestion links are displayed (see, e.g., Japanese Patent Application Publication No. JP-A-11-2538).